This invention relates to loudspeakers, and more particularly to the selection of material forming the supporting means of the diaphragm and the construction of the supporting means.
In a loudspeaker such as for instance a direct radiation type loudspeaker as shown in FIG. 1, the peripheral portion of the diaphragm 10 in particular form is, in general, supported by a supporting means 11 called an edge, and the diaphragm 10 is vibrated by a voice coil 12 fixedly secured to the central opening of the diaphragm 10. In this case, the vibration of the diaphragm 10 and accordingly the voice coil 12 is suppressed by a damper 13 and an edge 11. Furthermore, a cap 14 is provided at the center of the diaphragm 10 so as to prevent the passage of the air through the diaphragm.
Since both of the edge 11 and the damper 13 serve to support the diaphragm 10, they will be hereinafter referred to as "a supporting means" when applicable.
Heretofore, in the loudspeaker of this type, the diaphragm is made of paper. Recently, a diaphragm made of carbon fibers has been proposed in the art. However, since the weight is an important factor affecting the characteristics of such a loudspeaker, a method of intentionally coating the diaphragm with a damping agent thereby to increase the internal loss has not been employed. Furthermore, as the damping agent is applied to the edge of the loudspeaker, the response characteristic thereof to a small signal applied thereto is very low.
However, in the loudspeaker, it is desirable that the vibrating part thereof can operate as one unit without deformation and that the supporting means can respond to any small signal.